Changes in the Spectrum of Systemic Autoimmune and Autoinflammatory Diseases in Sub-Saharan Africa: A Cohort Study of 1,006 Patients in Senegal

Abstract

Introduction: Data on systemic diseases in sub-Saharan Africa remain limited despite a widening clinical spectrum and recognition of their contribution to chronic disease burden. In tropical environments, these conditions are often characterized by significant diagnostic delays and severe visceral involvement. This study reports on the comprehensive disease spectrum within a major Senegalese internal medicine department. Methods : We performed a descriptive, retrospective cohort study of all patients managed for systemic diseases in the Internal Medicine Department of Dalal Jamm National Hospital from August 29, 2016, to August 18, 2021. Diagnoses were cross-referenced against international criteria based on full clinical and paraclinical evidence. Results: During the study period, a total of 1,136 medical records were screened, and 130 were excluded due to insufficient data, resulting in 1,006 unique medical records analyzed. The mean age was 48.11 years, ranging from 3 to 91 years, with a clear female predominance of 82.03% and a sex ratio of 0.219. The median time to diagnosis was 3 years (range: 0 - 46 years; mode: 1 year). Chief complaints were dominated by joint involvements in 83.73% of cases, primarily presenting as polyarthritis in 60.6% of patients. A family history of inflammatory rheumatism was identified in 23.76% of the cohort. Autoimmune diseases represented 67.1% of the total cases, followed by autoinflammatory diseases at 19.4%, undifferentiated connective tissue diseases at 10.9%, systemic vasculitides at 2.1%, and granulomatoses at 0.5%. In the autoimmune group, rheumatoid arthritis predominated with 499 cases; Systemic Lupus Erythematosus (SLE) accounted for exactly 34 cases (3.4%). Among autoinflammatory conditions, polygenic forms like ankylosing spondylitis led with 89 cases, while a single monogenic case of Familial Mediterranean Fever was recorded with a diagnostic delay of 20 years. Beh?et’s disease led the vasculitis group with 14 cases. Methotrexate was the most common disease-modifying antirheumatic drug utilized, prescribed to 54.20% of patients on maintenance therapy. Conclusion: This cohort demonstrates a broad, diverse spectrum of systemic conditions in tropical settings, dominated by polygenic autoimmune and autoinflammatory disorders. Marked diagnostic delays persist for rare or monogenic diseases, arguing for the establishment of regional registries to support large-scale clinical trials.